I would assume so execpt for the fact that all Air Nomads were Airbenders, but this is not attributed to genetics, but to the high level of spirituallity of the Air Nomads. So which is it, genetics or spirituality?

Its never fully explained, but yes, bending does have a genetic component, otherwise we would see much fewer firebenders in the largely agnostic Fire Nation. The thing is that it is more or less random who gets bending and who doesn't, and since Watson and Crick don't vacation in the Avatar world, bending inheritence isn't mapped out very well.

I'm actually not so sure how much airbending can be attributed to spirituality. I think its the only bending allele thats dominant as opposed to being more or less randomly distributed, with the spirituality origin being used as an explination due to a lack of understanding of genetics in the Avatar world.

Ironically, it seems that a Nation's bending population also correlates with its element's placement in the Avatar Cycle:

Firebenders are confirmed to have the largest bending population. The Air Nomads were aided by their spirituality, but I am sure that without it, they'd probably lead in second place. Waterbenders are somewhat common amongst their people, but the Earth Kingdom was confirmed to have the smallest bending population, confirming the position of Waterbenders in terms of population rank against the other types.

I wondered this too - you see bending ability run in families, but then you get cases like the identical twins in AtLA (the episode where the gang saves a village from a volcano), one who is an earthbender, one who isn't. But it doesn't seem like bending is a learned ability (I mean, bending like a master takes training, but I get the impression that it becomes apparent from an early age if someone has bending ability). So I guess it probably would be genetic, but just a really complicated relationship between genotype and phenotype?

The Air Nomad Critic, I like your idea about airbending being a dominant allele - that had never occurred to me before.

Something else I wondered - the royal family of the fire nation all seem to be really strong firebenders - can you imagine the shame if a royal child was born without firebending? Zuko seemed to get enough stick for not being very good at it as a child. It's not inconceivable that just by chance, a strong firebending bloodline produces a non-bender heir. What would happen to the kid? In contrast, it doesn't look like the royal family of the earth kingdom are able to earthbend - interesting difference in cultures, isn't it? Even with so few benders among the earth population, why has it taken so long in earth kingdom history for a master earthbender to waltz in with her 'super powers' and take control as Kuvira has done?

Bending is genetic, if it wasn't there would be airbenders born from fire/water/earthbenders. But spirituality plays a big role too, probably deciding if a person will be a bender or a nonbender while genetic decides what the person will bend.

Uh, okay. There is a common theory that the reason why all Air Nomads are Airbenders because the Airbending Allele is dominant.

An allele is "a form of a gene." To use the example of hair color, I believe there are alleles for black, brown, red, & blond.

Red hair is recessive, so you need 2 copies of the red hair allele in order to have red hair.

Black hair is dominant, so if you have 1 black hair allele, you will have black hair. This is why people think that the Airbending allele must be dominant, but a dominant allele can't explain why all Air Nomads were Airbenders. That would require any "not airbender" alleles to be rare or even nonexistent among the Nomads--whether dominant OR recessive.

The dominant/recessive inheritance pattern is the simplest, but not the only one. For example, human skin color is "codominant," which means that the child's skin color will usually be halfway in between his or her parents. And things get more complicated than that, with most traits being controlled by multiple genes. Also, some traits are affected by other factors.

Yes. So basically the Aa letters in biology are alleles? I call them alelos, sorry i didn't know they were called alleles.

Yeah, essentially. Is that the term in a different language, or something?

But what do you think is the spiritual part in that?

Haven't the foggiest. Mike & Bryan almost seemed to contradict that when they had Aang's children consist of a waterbender, a nonbender, & an airbender. His Air Nomad Spirituality didn't seem to have any special clout.

Soob.sun wrote:I wondered this too - you see bending ability run in families, but then you get cases like the identical twins in AtLA (the episode where the gang saves a village from a volcano), one who is an earthbender, one who isn't. But it doesn't seem like bending is a learned ability (I mean, bending like a master takes training, but I get the impression that it becomes apparent from an early age if someone has bending ability).

It's clear cut that it is Genetic because I've never herd of a bender being born to a non-bender

as the twins they might not be identical (I have an older brother that looks just like me)

is everyone forgetting toph? Her parents were non-benders and she still was an earthbender. She didn't get her bending from genes, but by learning it from badger moles as stated in season 3 episode 13 (the firebending masters). And remember how all the nations original benders learned bending from the original source (water from the ocean and moon, earth from the badger moles, air from the sky bison, and fire fro mthe drgons.) I do thing that there could be a genetic aspect to it in terms of what element you can bend, but i think any non-bender could learn bending like toph if they found the original source of bending and were connected to it like toph was to badger moles.

While I do appreciate the spiritual explaination can work, it's hard to quantify properly. And it isn't as though genetics proper are incapable of explaining the phenonemenon. You simply have to apply more than one gene. For example, consider this system:

Nn, and t^o < t^E < t^W < t^F < T^A

The first gene, Nn, simply controls whether or not a person has the potential for bending. Given Katara and Toph's lineage from non-bender families, non-bending appears to be dominant. But in a true dominant-recessive system, it would be impossible for two benders like Katara and Aang to have a non-bending child. Thus the second gene, which controls the type of bending. Non-bending children of benders also appear to be recessive, taking into account Toph's children, Katara and Aang's children, and Mako and Bolin. So the non-element type is the most recessive. The rest of the dominance hierarchy ensures that any given person can only bend one element. I based the order on suppositions above about the prevalence of certain types of benders. If nearly every Air Nomad is an airbender, for example, then they should have the most dominant type.

If we apply this system to Katara and Aang, we are able to produce the cloudbabies if we assume that both have a recessive t^o. Katara's genotype would be nn t^W t^o and Aang's would be nn T^A t^o. If you calculate the probabilities, there's a 1/4 chance of a waterbender nn t^W t^o (Kya), a 1/4 chance of a non-bender nn t^o t^o (Bumi), and a 1/2 chance of an airbender (Tenzin) nn T^A t^W or nn T^A t^o. Given that Tenzin had no waterbending children, he is most likely not a carrier for waterbending. But if his wife has one or more T^A allele, that could swamp out the waterbending enough that it might not show until a later generation.

Pema being a nonbender but still producing four bending children makes her a bit of an anomally in this system. Statistically, whether her non-bending came from an N allele or two t^o alleles, we should expect that paired with Tenzin, half her children will express bending and the other half will not. So it's possible that the system is not accurate to the real genetics. But even if such an occurance is statsitcally unlikely, isn't outside the realm of possibility, and the system is still usable.

Of course identical twins should have the same bending ability- if there really was an instance where they didn't (I don't remember such a thing, but it's been a long time since I saw the show) that could come down to gene penetrance. Which could work even in a one-gene system. But again that's hard to quantify reliably.

Which element a kid can get seems to be genetic (with the possible exception of airbending; we don't know how much Harmonic Convergence threw that out of whack, or whether or not any Bopals could inherit their mom's element). Whether or not they're benders at all seems to be almost random; we've seen several nonbender parents with bender kids (the Watersibs' parents, the Beifongs, Ursa and Ikem).

all these people arguing and no one was really paying attention to the show? I mean it's clearly more complex than just making a choice between the 2.

every element has its own kind of energy and if ur body happens to have that energy flowing on/in u you'll be able to bend.

it doesn't matter what makes u have that energy on/in you but certainly, there are many factors including:

genetic heredity, the avatar or the turtle lions (or whatever) closing/opening or just basically gives u that energy, u get it urself through training, like how some characters in the show learned the bending from animals and the moon.

(it isn't clear if anyone can learn to bend from the animals or it depends on their personality and physical and spiritual state of their body)

it doesn't seem they explained deeply these things but apparently even if anyone could learn bending by training and trying to get these energies to flow inside u by some spiritual actions people don't seem to care enough to even try...

it just feels like they're agnostic or don't care about their spirituality (aka religion) and a world where Buddhism seems to be the only religion out there?

anyways it's pretty complex therefore u can't just make a simple choice between genetics and spirituality.